Thermal processing apparatus and thermal processing method

ABSTRACT

In a thermal processing apparatus irradiating a substrate with light from a lamp for heating the substrate, an opening is formed in a reflector for mounting a camera unit. The camera unit images three portions of an auxiliary ring supporting the substrate, for obtaining the position of the center of the auxiliary ring before the thermal processing apparatus receives the substrate therein. The camera unit further images the substrate for obtaining the position of the center of the substrate before the thermal processing apparatus receives the substrate therein and places the same on the auxiliary ring. The thermal processing apparatus moves the substrate so that the center thereof coincides with the center of the auxiliary ring, and thereafter places the former on the latter. Thus, the auxiliary ring can be so designed as to reduce overlaps of the auxiliary ring and the outer edge of the substrate while the overlaps can be rendered uniform over the entire circumference of the substrate for improving temperature uniformity of the substrate.

CROSS REFERENCE TO RELATED APPLICATION

This is a division under 37 C.F.R. §1.53(b) of prior application Ser.No. 10/394,895, filed Mar. 21, 2003 by Toshiyuki KOBAYASHI, et al.,entitled THERMAL PROCESSING APPARATUS AND THERMAL PROCESSING METHOD, thecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique of heating a substrate withlight.

2. Description of the Background Art

As the requirement for refinement of a device such as a semiconductordevice is increased, a rapid thermal process (hereinafter abbreviated as“RTP”) has been going to play an important role as one of heating stepsfor a semiconductor substrate (hereinafter referred to as “substrate”).The RTP is performed mainly with a lamp employed as a heat source.Briefly stated, a processing chamber is kept in a prescribed gasatmosphere for heating a substrate to a prescribed temperature (e.g.,1100° C.) in several minutes (temperature increase step), maintainingthe substrate at the temperature for a constant time (e.g., several 10seconds) (holding step) and thereafter turning off the lamp therebyrapidly cooling the substrate.

The RTP is employed for performing processing such as that of preventingan impurity from thermal re-diffusion in a junction layer of atransistor formed on a substrate or that of reducing the thickness of aninsulator film such as an oxide film, for example, which has been hardto implement through prolonged thermal processing in a conventionalelectric furnace.

A thermal processing apparatus performing the RTP may be provided withan auxiliary ring coming into contact with the outer edge of a substratethereby supporting the substrate and a screening ring covering the outerside of the auxiliary ring. The auxiliary ring is integrally heated withthe substrate thereby improving temperature uniformity on the surface ofthe substrate while preventing a thermometer arranged on the back sideof the substrate for measuring the temperature of the substrate duringthe RTP from direct incidence of light from a lamp. The screening ringis provided for forming an optical labyrinth on the outer edge of theauxiliary ring while preventing the thermometer from incidence of lightfrom outside the auxiliary ring.

The auxiliary ring has tolerance in preparation, while the center of thesubstrate placed thereon deviates from the center of the auxiliary ring.The auxiliary ring is arranged in the apparatus in a state placed on asupport member, and hence the position of the auxiliary ring changes dueto difference between the thermal expansion coefficients of theauxiliary ring and the support member when thermal processing isrepeated. Particularly when processing a large-sized substrate having adiameter of about 300 mm, movement of the auxiliary ring is increased.In consideration of the aforementioned various factors, a conventionalthermal processing apparatus is so designed as to sufficiently provideoverlaps of the substrate and the auxiliary ring so that no clearance isdefined between the substrate and the auxiliary ring when the former isplaced on the latter to introduce light from the lamp into thethermometer.

Further, clearances (the so-called “slacks”) are provided on engagingportions between the auxiliary and screening rings and memberssupporting these rings respectively, for preventing the rings fromcracking resulting from expansion in heating. When the thermalprocessing is repeated, therefore, the positions of the auxiliary ringand the screening ring change, i.e., the positions of the centers of theauxiliary ring and the screening ring deviate from the center of thesubstrate, due to difference between the temperatures or the thermalexpansion coefficients of the rings and the members supporting the same.In consideration of this factor, the conventional thermal processingapparatus is so designed as to sufficiently increase the overlapsbetween these structures so that no clearance is defined between thesubstrate and the auxiliary ring or between the auxiliary ring and thescreening ring to introduce the light from the lamp into the thermometeralso when displacement is caused.

If the substrate and the auxiliary ring largely overlap with each other,however, the thermal capacity of the outer edge of the substrate(apparent thermal capacity in consideration of influence by the thermalcapacity of the auxiliary ring) is increased in heating, to result intemperature irregularity (such ununiformity that the temperature of theouter edge is relatively reduced in heating and relatively increased incooling) allowing no compensation through adjustment of the lamp outputbetween a portion around the center of the substrate and the outer edgethereof. Also when the centers of the substrate and the auxiliary ringdeviate from each other, the overlaps get inconstant on the outer edgeof the substrate, and hence the thermal capacity gets ununiform on theouter edge of the substrate, leading to temperature irregularity.

When the auxiliary ring and the screening ring largely overlap with eachother, there is such a possibility that the temperature is relativelyslowly increased on the outer edge of the auxiliary ring when heatingthe substrate, to crack the auxiliary ring due to excess stressresulting from temperature difference between the outer edge and theinner periphery. When the centers of the auxiliary ring and thescreening ring deviate from each other, it follows that temperatureuniformity of the auxiliary ring is reduced to also reduce temperatureuniformity of the substrate as a result.

Consequently, it is difficult to suppress dispersion of the thickness information of an oxide film or the like, for example, within a range morestrictly required in the future. Exemplary formation of an oxide film ina conventional thermal processing apparatus is now described.

FIG. 1 illustrates time change of a substrate temperature in the RTP.The horizontal axis and the vertical axis show the time and thesubstrate temperature respectively. Referring to FIG. 1, a temperatureincrease step of increasing the substrate temperature is carried outbetween times t1 and t2, and a holding step of keeping the substratetemperature at a target level A is carried out between the time t2 and atime t3. FIG. 2 shows the relation between positions on the substrateand the thickness of the oxide film in the case of performing such anRTP. The horizontal axis and the vertical axis show the distance fromthe center of the substrate and the average thickness of the oxide filmwith respect to the distance respectively.

As shown in FIG. 2, the thickness is stable inside a portion around adistance R1, i.e., the side of the center of the substrate, while thethickness is abruptly increased when approaching a distance R2corresponding to the outer edge of the substrate. This is conceivablybecause the temperature of the auxiliary ring exceeds the substratetemperature in the holding step and the temperature of the outer edge ofthe substrate exceeds that of the inner part due to heat conducted fromthe auxiliary ring.

Following requirement for further pattern refinement, reduction oftemperature irregularity of substrates resulting from influence byrespective ring-shaped members (an auxiliary ring and a screening ring)provided outside the substrates has recently been increasingly required.

SUMMARY OF THE INVENTION

The present invention is intended for a technique for reducingdisplacement between a substrate and an auxiliary ring therebysuppressing overlaps and rendering the overlaps constant for improvingtemperature uniformity of the substrate in heating.

A thermal processing apparatus according to a preferred embodiment ofthe present invention, capable of heating a substrate with light,comprises a lamp irradiating the substrate with the light, a ringenclosing the outer edge of the substrate and outwardly spreading fromthe outer edge, and an image pickup system capturing images of aplurality of portions of the ring.

Thus, the thermal processing apparatus can correctly position thesubstrate in response to the ring. When placing the substrate on thering, the thermal processing apparatus can render overlaps small andconstant, for improving temperature uniformity of the substrate inthermal processing.

The present invention is also directed to a thermal processing apparatuscomprising a lamp irradiating a substrate with light, a ring memberenclosing the outer edge of the substrate and outwardly spreading fromthe outer edge (this ring member has a first surface) and a supportmember supporting the ring member (this support member has a secondsurface opposed to the first surface).

Thus, a clearance between the first and second surfaces is reduced dueto contraction of the ring member or the support member in temperaturereduction, whereby the thermal processing apparatus can limitdisplacement of the ring member.

Preferably, the ring member is a ring supporting the outer edge of thesubstrate from below.

Thus, the thermal processing apparatus can block light directed downwardbelow the substrate and improve temperature uniformity of the substratein heating.

The present invention is also directed to a thermal processing apparatuscomprising a lamp irradiating a substrate with light and a ring havingan annular support part coming into contact with the outer edge of thesubstrate for supporting the outer edge from below and outwardlyspreading from the outer edge, while a numerical value obtained in termsof “mm²” of the product (area) of a support width of a portion where theouter edge of the substrate and the support part overlap with each otherand the thickness of the support part is rendered not more than twice anumerical value obtained in terms of “mm” of the thickness (length) ofthe substrate.

Thus, the thermal processing apparatus employing the lamp can improvetemperature uniformity of the heated substrate.

Accordingly, an object of the present invention is to improve uniformityof a substrate temperature in processing of irradiating the substratewith light from a lamp for heating the substrate.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the relation between the temperature of a substrateand the time;

FIG. 2 illustrates the relation between a distance from the center ofthe substrate and the thickness of an oxide film;

FIG. 3 is a longitudinal sectional view showing the structure of athermal processing apparatus according to a first preferred embodimentof the present invention;

FIG. 4 is a plan view showing the inside of a cylindrical member;

FIG. 5 is an enlarged sectional view showing a support ring groupsupporting a substrate;

FIG. 6 is a block diagram showing the connectional relation betweenimage pickup parts and the remaining structures of the thermalprocessing apparatus;

FIG. 7 illustrates the flow of operations of the thermal processingapparatus;

FIG. 8 illustrates images captured in the image pickup parts;

FIG. 9 is a front view of the thermal processing apparatus receiving thesubstrate;

FIG. 10 is a plan view of the thermal processing apparatus receiving thesubstrate;

FIG. 11 illustrates images captured in the image pickup parts;

FIG. 12 is a plan view showing a thermal processing apparatus accordingto a second preferred embodiment of the present invention;

FIG. 13 is a plan view showing a thermal processing apparatus accordingto a third preferred embodiment of the present invention;

FIG. 14 is a block diagram showing the connectional relation between animage pickup part and the remaining structures of the thermal processingapparatus;

FIG. 15 illustrates the flow of operations of the thermal processingapparatus;

FIG. 16 illustrates the flow of operations of a thermal processingapparatus according to a fourth preferred embodiment of the presentinvention;

FIG. 17 illustrates images captured in image pickup parts;

FIG. 18 is a diagram for illustrating a method of obtaining movement ofa substrate;

FIG. 19 is a plan view showing a thermal processing apparatus accordingto a fifth preferred embodiment of the present invention;

FIG. 20 is a diagram for illustrating a method of obtaining movement ofa substrate;

FIG. 21 is a longitudinal sectional view showing a thermal processingapparatus according to a sixth preferred embodiment of the presentinvention;

FIG. 22 is a plan view showing the thermal processing apparatus;

FIG. 23 illustrates a positioned auxiliary ring;

FIG. 24 is a longitudinal sectional view showing a thermal processingapparatus according to a seventh preferred embodiment of the presentinvention;

FIG. 25 is a plan view showing the inside of a screening ring;

FIG. 26 is an enlarged sectional view showing an auxiliary ring groupsupporting a substrate;

FIG. 27 is an enlarged sectional view showing the auxiliary ring groupand the screening ring;

FIG. 28 is an enlarged sectional view showing the auxiliary ring groupand the screening ring in heating;

FIG. 29 illustrates another exemplary screening ring;

FIG. 30 illustrates another exemplary auxiliary ring group and stillanother exemplary screening ring;

FIGS. 31 and 32 are longitudinal sectional views showing a thermalprocessing apparatus according to an eighth preferred embodiment of thepresent invention;

FIG. 33 is a block diagram showing lamps and a lamp control part;

FIG. 34 is a plan view showing the inside of a cylindrical member;

FIG. 35 is an enlarged sectional view showing a support ring groupsupporting a substrate;

FIG. 36 illustrates the relation between thickness difference D and aproduct (T×W); and

FIG. 37 illustrates exemplary values of a support part thickness T and asupport width W.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 is a longitudinal sectional view showing the structure of athermal processing apparatus 1 according to a first preferred embodimentof the present invention. FIG. 3 omits parallel oblique lines withrespect to sections of details.

The thermal processing apparatus 1 irradiates a substrate 9 with lightin a prescribed atmosphere thereby performing various thermal processing(oxidization, annealing, CVD etc.) accompanied by heating. In thethermal processing apparatus 1, a body part 11 forming the apparatusbody, a lid part 12 covering the upper portion of the body part 11 and areflector 13 arranged on the central bottom surface of the body part 11form a chamber. A chamber window 21 of quartz vertically partitions theinternal space of the chamber, and a support ring group 30 supports thesubstrate 9 in a lower processing space 11 a. An O-ring (not shown)seals the clearance between the chamber window 21 and the body part 11,which has a cylindrical inner side surface. A plurality of gas inlets111 and a plurality of outlets 112 are formed on the side wall of thebody part 11. The processing space 11 a performs gas replacement by(enforcedly) discharging gas from the outlets 112 while introducing gas(e.g., nitrogen, oxygen or the like) responsive to the type ofprocessing performed on the substrate 9 through the gas inlets 111. Thethermal processing apparatus 1 is provided with a shower plate 22 ofquartz formed with a large number of holes between the substrate 9 andthe chamber window 21, for homogeneously supplying the gas introducedfrom the gas inlets 111 to the upper surface of the substrate 9 throughthe shower plate 22. The gas employed for the processing is guided tothe outlets 112 from below the processing space 11 a.

A cylindrical member 33 centered at a central axis 1 a of the apparatus1 supports the support ring group 30, while a coupling member 331 ismounted on the lower end of the cylindrical member 33. Another couplingmember 332 opposed to the coupling member 331 is provided under the bodypart 11 so that the coupling members 331 and 332 form a magneticcoupling mechanism. The coupling member 332 rotates about the centralaxis 1 a through a motor 333. Thus, the coupling member 331 provided inthe body part 11 rotates due to magnetic action, while the substrate 9and the support ring group 30 rotate about the central axis 1 a whilekeeping the direction of the main surface constant.

FIG. 4 illustrates the inside of the cylindrical member 33 along arrowsA in FIG. 3, and FIG. 5 is an enlarged sectional view showing thesupport ring group 30 supporting the substrate 9. As shown in FIGS. 4and 5, the support ring group 30 is formed by an annular auxiliary ring31 receiving the substrate 9 thereon and an annular cushion ring 32supporting the auxiliary ring 31 from outside. Both of the auxiliaryring 31 and the cushion ring 32 are made of silicon carbide (SiC) havingspecific heat capacity close to that of the substrate 9, and theauxiliary ring 31 is heated integrally with the substrate 9 therebyimproving in-plane uniformity of the temperature of the substrate 9.

The auxiliary ring 31 has an annular support part 311 projecting towardthe central axis 1 a on its inner peripheral surface 310. The supportpart 311 comes into contact with an outer edge 91 of the substrate 9transported into the processing space 11 a by an external transportmechanism from below thereby supporting the substrate 9. When thesubstrate 9 is placed on the auxiliary ring 31, an outer peripheralsurface 90 of the substrate 9 and an inner peripheral surface 310 of theauxiliary ring 31 are opposed to each other while the auxiliary ring 31is positioned to outwardly spread from the outer edge 91 of thesubstrate 9.

The cylindrical member 33 supports the cushion ring 32 supporting theauxiliary ring 31 (see FIG. 3). As shown in FIG. 5, engaging portions391 and 392 between the auxiliary ring 31 and the cushion ring 32 andbetween the cushion ring 32 and the cylindrical member 33 haveclearances (slacks) respectively. Also when swollen with heat,therefore, the auxiliary ring 31 and the cushion ring 32 are preventedfrom cracking resulting from excess stress. The auxiliary ring 31 andthe cushion ring 32 may be partly recessed as long as their functionsare fulfilled.

As shown in FIG. 3, the lower surface of the lid part 12 of the thermalprocessing apparatus 1 defines a reflecting surface (hereinafterreferred to as “reflector”) 121 opposed to the upper surface of thesubstrate 9, and a bar-shaped upper lamp group 41 is arranged along thereflector 121 so that respective lamps are along a direction X. Thereflector 121 reflects a component of light upwardly emitted from theupper lamp group 41 and applies the same to the substrate 9. The upperlamp group 41 is formed by infrared halogen lamps, for example. Abar-shaped lower lamp group 42 is arranged under the upper lamp group41, i.e., between the upper lamp group 41 and the substrate 9, so thatrespective lamps are along a direction Y perpendicularly to the upperlamp group 41.

Each of the upper and lower lamp groups 41 and 42 is divided into smallgroups in response to distances from the central axis 1 a, and thegroups are individually connected to a lamp control part and suppliedwith power independently of each other.

A plurality of radiation thermometers 51 are mounted under the substrate9 outwardly from the central axis 1 a. The radiation thermometers 51receive infrared light from the substrate 9 through a window member 50provided on the reflector 13 thereby measuring the temperature of thesubstrate 9. The plurality of radiation thermometers 51 measure thetemperature of the substrate 9 placed on the support ring group 30 androtated in response to distances from the central axis 1 a. At thistime, the substrate 9, the support ring group 30 and the cylindricalmember 33 inhibit infrared radiation from the lamp groups 41 and 42 fromentering the radiation thermometers 51, so that the radiationthermometers 51 correctly measure the temperature.

When performing processing accompanied by heating, the thermalprocessing apparatus 1 controls power supplied to each group of the lampgroups 41 and 42 in response to results of measurement of the radiationthermometers 51. At this time, a rotation mechanism formed by the motor333 and the coupling mechanism rotates the substrate 9 and the supportring group 30, and the thermal processing apparatus 1 controls heatingof the substrate 9 so that the temperature of the substrate 9 is asuniform as possible.

The thermal processing apparatus 1 is further provided with three cameraunits 6 on the lid part 12. The camera units 6 capture images of theauxiliary ring 31 through openings 120 of 5 mm in diameter, for example,formed in the lid part 12. The camera units 6 comprise image pickupparts 62 and light source parts 63 mounted on optical units 61, so thathalf mirrors 611 provided in the optical units 61 reflect light from thelight source parts 63 and guide the reflected light to the auxiliaryring 31 as illumination light through the openings 120. Light from theauxiliary ring 31 is transmitted through the half mirrors 611 and guidedto the image pickup parts 62. The three camera units 6 are mounted onpositions rotated by 120° from each other about the central axis 1 a, asshown by phantom lines in FIG. 4.

As shown in FIG. 3, a plurality of lift mechanisms 71 (FIG. 3illustrates only a single lift mechanism 71 with two-dot chain lines)vertically moving lift pins 711 are mounted on the lower surface of thereflector 13 provided on the lower portion of the apparatus 1, while anopenable/closable gate 115 is provided on the side surface of the bodypart 11. When an external transport robot 8 (see FIG. 6) introduces ordischarges the substrate 9 into or from the thermal processing apparatus1 through the gate 115, the lift mechanisms 71 bring the lift pins 711into contact with the lower surface of the substrate 9 for verticallymoving the substrate 9, thereby transferring the substrate 9 between anarm 82 (see FIG. 9) of the transport robot 8 and the lift pins 711.

FIG. 6 is a block diagram showing the connectional relation between theimage pickup parts 62 of the three camera units 6 and the remainingstructures of the thermal processing apparatus 1. The image pickup parts62 are connected to an image processing circuit 65, which in turnprocesses images captured by the image pickup parts 62. The imageprocessing circuit 65 inputs results of the processing in a totalcontrol part 10 controlling total operations of the thermal processingapparatus 1, so that the total control part 10 controls the externaltransport robot 8 and the lift mechanisms 71. Thus, the thermalprocessing apparatus 1 correctly matches the centers of the substrate 9and the auxiliary ring 31 with each other when receiving the substrate 9as described later.

The total operations of the thermal processing apparatus 1 are nowdescribed mainly with reference to an operation of receiving thesubstrate 9 therein.

FIG. 7 illustrates the flow of the operations of the thermal processingapparatus 1. First, the three camera units 6 capture images of theauxiliary ring 31 before the substrate 9 is introduced into the thermalprocessing apparatus 1 (step S11). FIG. 8 illustrates three images 601captured by the image pickup parts 62 in consideration of the directionsof the captured images 601.

Then, the thermal processing apparatus 1 obtains the position of thecenter of the auxiliary ring 31 with the three images 601 (step S12).More specifically, the image pickup parts 62 input the captured images601 in the image processing circuit 65 as shown in FIG. 6, so that theimage processing circuit 65 performs processing such as edge extractionand detection of tangential lines with reference to the central axis 1 aof the apparatus 1 in processed areas 602 shown in FIG. 8 and specifiespoints 310 a on the inner peripheral surface 310 (see FIG. 5) of theauxiliary ring 31. The thermal processing apparatus 1 previously setsthe processed areas 602 and a method of detecting the arcuate tangentiallines, for example, by introducing a dummy disk having a known shape.

The thermal processing apparatus 1 previously captures the positions ofthe three camera units 6 through polar coordinates expressed by thedistances and directions from the central axis 1 a thereof, for example,and also previously inputs the imaging ranges of the camera units 6 inthe total control part 10. When receiving the coordinates of the threepoints 310 a in the images 601, the total control part 10 obtains theabsolute positions of the three points 310 a with reference to thethermal processing apparatus 1, and further obtains the centercoordinates of a circle passing through the three points 310 a. In otherwords, the total control part 10 substitutes the coordinates of thethree points 310 a in an equation of the circle with unknowns of thecenter coordinates of the auxiliary ring 31 and the radius of the innerperipheral surface 310 and solves the equation, thereby specifying theposition of the center of the auxiliary ring 31 (with respect to thecentral axis 1 a, for example) and the radius of the inner peripheralsurface 310.

Then, the external transport robot 8 introduces the substrate 9 into thethermal processing apparatus 1, i.e., into the chamber (step S13). FIGS.9 and 10 are a front view and a plan view showing the substrate 9introduced into the thermal processing apparatus 1 respectively.

The transport robot 8 reciprocates the arm 82 holding the substrate 9with respect to the thermal processing apparatus 1 through a frog legmechanism 81, which in turn is rotated by a rotation mechanism 83 abouta vertical axis. The total control part 10 controls the transport robot8 to introduce the substrate 9 temporarily to a position where thecenter of the substrate 9 substantially coincides with the central axis1 a of the thermal processing apparatus 1. Thus, the thermal processingapparatus 1 positions the outer peripheral surface 90 (see FIG. 5) ofthe substrate 9 under the camera units 6.

In this state, the camera units 6 capture images of the outer edge 91 ofthe substrate 9 again (step S14). FIG. 11 illustrates images 605captured by the three image pickup parts 62. The image processingcircuit 65 performs image processing on processed areas 602 in theimages 605 similarly to the step S12, and specifies points 90 a on theouter peripheral surface 90 of the substrate 9. The total control part10 obtains the center of a circle passing through the three points 90 athereby calculating the position of the center of the substrate 9 (withrespect to the central axis 1 a, for example) (step S15).

The total control part 10 obtains displacement of the center of thesubstrate 9 with respect to the center of the auxiliary ring 31 asmotion vectors in the directions X and Y, for example, and controls thetransport robot 8 to match the centers of the substrate 9 and theauxiliary ring 31 with each other (step S16). While the transport robot8 rotates/moves the substrate 9 with the rotation mechanism 83 as shownin FIG. 10 and changes the radius of rotation with the frog legmechanism 81, justification of the substrate 9 is slight with respect tothe size of the substrate 9, e.g., within 2 mm for the substrate 9 of300 mm in diameter, and hence the frog leg mechanism 81 performspositioning in the direction Y and the rotation mechanism 83 performspositioning in the direction X.

The thermal processing apparatus 1 sets positioning accuracy to not morethan 0.1 mm, for example, while also setting the resolution of the imagepickup parts 62 imaging areas of about 40 mm square through CCDs eachhaving at least 512 by 480 pixels to not more than 0.1 mm.

Thereafter the total control part 10 controls the lift mechanisms 71 sothat the lift pins 711 push up the substrate 9, the arm 82 retreatsoutward and the lift pins 711 move down thereby placing the substrate 9on the support part 311 of the auxiliary ring 31 (step S17). Due to theaforementioned operations, the thermal processing apparatus 1 places thesubstrate 9 on the auxiliary ring 31 while matching the centers thereofwith each other so that overlaps of the support part 311 of theauxiliary ring 31 and the substrate 9 have uniform widths along theoverall outer periphery of the substrate 9.

When placing the substrate 9 on the auxiliary ring 31, the thermalprocessing apparatus 1 closes the gate 115 shown in FIG. 3, supplies theprocessing space 11 a with an atmosphere of processing gas and rotatesthe substrate 9 with the auxiliary ring 31 for thermally processing thesubstrate 9 with the lamps (step S118). When completing the thermalprocessing, the thermal processing apparatus 1 replaces the gas in theprocessing space 11 a and opens the gate 115, so that the lift pins 711push up the substrate 9. The transport robot 8 inserts the arm 82 into aportion under the substrate 9, so that the lift pins 711 move down toplace the substrate 9 on the arm 82. The arm 82 discharges the substrate9 from the thermal processing apparatus 1 (step S19).

The aforementioned thermal processing apparatus 1 according to the firstpreferred embodiment captures the images 601 of the auxiliary ring 31with the three image pickup parts 62 and obtains the position of thecenter of the auxiliary ring 31 before the transport robot 8 introducesthe substrate 9 into the same. Further, the thermal processing apparatus1 captures the images 605 of the outer edge 91 of the substrate 9 withthe three image pickup parts 62 and obtains the position of the centerof the substrate 9 before placing the introduced substrate 9 on theauxiliary ring 31. Therefore, the thermal processing apparatus 1 canobtain the centers of the auxiliary ring 31 and the substrate 9 alsowhen the diameter of the auxiliary ring 31 (more correctly, the diameterof the inner peripheral surface 310) or the outer diameter of thesubstrate 9 is unknown.

Thus, also when the auxiliary ring 31 positionally deviates from thecentral axis 1 a of the apparatus 1, the thermal processing apparatus 1can place the substrate 9 on the auxiliary ring 31 so that the centersthereof coincide with each other, thereby rendering the overlaps of theouter edge 91 of the substrate 9 and the auxiliary ring 31 constant.Consequently, the shape of the auxiliary ring 31 can be so designed asto sufficiently reduce the overlaps, and thermal capacity on the outeredge 91 of the substrate 9 can be suppressed small in consideration ofheat transfer between the substrate 9 and the auxiliary ring 31.Further, the thermal capacity of the outer edge 91 can be inhibited fromdispersion due to the constant overlaps. Consequently, the thermalprocessing apparatus 1 can improve temperature uniformity of the overallsubstrate 9 for implementing proper thermal processing on the substrate9.

The thermal processing apparatus 1 according to the first preferredembodiment, measuring the auxiliary ring 31 and the substrate 9 with thethree camera units 6, may alternatively measure the substrate 9 beforereceiving the same. For example, a plurality of camera units 85 may beprovided outside the thermal processing apparatus 1 as shown by phantomlines in FIG. 9, for obtaining the center of the substrate 9 held by thetransport robot 8. In this case, it follows that the steps S14 and S15shown in FIG. 7 are separately carried out before the transport robot 8introduces the substrate 9 into the thermal processing apparatus 1.Further alternatively, the thermal processing apparatus 1 maymechanically position the substrate 9 to locate the center of thesubstrate 9 on a prescribed position with respect to the arm 82.

FIG. 12 illustrates a thermal processing apparatus 1 according to asecond preferred embodiment of the present invention in a similar mannerto FIG. 10. The thermal processing apparatus 1 according to the secondpreferred embodiment is similar to that according to the first preferredembodiment except that two camera units 6 are provided at an angle ofabout 90° with respect to a central axis 1 a of the apparatus 1.

When the thermal processing apparatus 1 according to the secondpreferred embodiment is manufactured, the diameter of an innerperipheral surface 310 of an auxiliary ring 31 similar to that shown inFIG. 5 is previously measured while the outer diameter of a substrate 9is also previously measured in processing. The thermal processingapparatus 1 captures images of the auxiliary ring 31 with the two cameraunits 6 before receiving the substrate 9, so that an image processingcircuit 65 (see FIG. 6) obtains two points, corresponding to the points310 a shown in FIG. 8, on an inner peripheral surface 310 of theauxiliary ring 31 similarly to that of the thermal processing apparatus1 according to the first preferred embodiment, and a total control part10 obtains the position of the center of the auxiliary ring 31 on thebasis of the positions of the two points on the auxiliary ring 31 andthe previously measured diameter of the inner peripheral surface 310 ofthe auxiliary ring 31. In other words, the total control part 10substitutes the coordinates of the two points in an equation of a circlehaving the center coordinates of the auxiliary ring 31 as unknowns andsolves the equation, thereby specifying the position of the center ofthe auxiliary ring 31 with respect to the central axis 1 a, for example.

Also immediately after introduction of the substrate 9, the thermalprocessing apparatus 1 images an outer edge 91 of the substrate 9 withthe two camera units 6 so that the image processing circuit 65 obtainsthe positions of two points, corresponding to the points 90 a in FIG.11, on the outer peripheral surface 90 of the substrate 9 and the totalcontrol part 10 obtains the position of the center of the substrate 9 onthe basis of the positions of these points and the outer diameter of thesubstrate 9.

Thereafter the total control part 10 controls a transport robot 8 tomatch the centers of the substrate 9 and the auxiliary ring 31 with eachother, similarly to the first preferred embodiment. Thus, the transportrobot 8 places the substrate 9 on a prescribed position of the auxiliaryring 31, so that the thermal processing apparatus 1 thermally processesthe substrate 9.

When the diameter of a specific portion such as the inner peripheralsurface 310 of the auxiliary ring 31 and the outer diameter of thesubstrate 9 are known as described above, the thermal processingapparatus 1 can match the centers of the substrate 9 and the auxiliaryring 31 with each other and place the former on the latter also when thesame is provided with only two camera units 6.

Alternatively, camera units provided outside the thermal processingapparatus 1 may measure the central position of the substrate 9, and itfollows that the thermal processing apparatus 1 measures only theposition of the center of the auxiliary ring 31 in this case.

FIG. 13 illustrates a thermal processing apparatus 1 according to athird preferred embodiment of the present invention in a similar mannerto FIG. 10. The thermal processing apparatus 1 according to the thirdpreferred embodiment is similar to that according to the first preferredembodiment except that the same is provided with only one camera unit 6.With reference to the third embodiment, it is assumed that the positionof the center of a substrate 9 is captured before the same is introducedinto the thermal processing apparatus 1 and the diameter of an innerperipheral surface 310 of an auxiliary ring 31 similar to that shown inFIG. 5 is also previously captured.

FIG. 14 is a block diagram showing the connectional relation between animage pickup part 62 of the camera unit 6 and the remaining structuresof the thermal processing apparatus 1 according to the third preferredembodiment, and FIG. 15 illustrates the flow of operations of thethermal processing apparatus 1 receiving the substrate 9.

According to the third preferred embodiment, the thermal processingapparatus 1 inputs the image captured by the image pickup part 62 in animage processing circuit 65 (step S21), so that a total control part 10thereafter controls a motor 333 similar to that shown in FIG. 3 and arotation mechanism 330 formed by the motor 333 and coupling members 331and 332 rotates the auxiliary ring 31 by 90°, for example (step S22).Then, the image pickup part 62 captures another image of the auxiliaryring 31 (step S23). Thus, it follows that the image processing circuit65 receives images of two portions of the auxiliary ring 31.

The image processing circuit 65 obtains specific points (on the innerperipheral surface 310 similar to that shown in FIG. 5) in the twoimages. The total control part 10 obtains the position of the center ofthe auxiliary ring 31 on the basis of the positions of these points andthe rotational angle of the auxiliary ring 31 (step S24). Morespecifically, the total control part 10 obtains the position of aspecific point in the previously captured image after rotating the sameabout a central axis 1 a and obtains a point separated from the obtainedposition and the position of a specific point in the subsequentlycaptured image toward the central axis 1 a by the radius of the innerperipheral surface 310 as the center of the auxiliary ring 31.

Thereafter the total control part 10 controls a transport robot 8 forintroducing the substrate 9 into a chamber and matching the centers ofthe substrate 9 and the auxiliary ring 31 with each other, and lift pins711 place the substrate 9 on the auxiliary ring 31 (steps S25 to S27;see FIG. 14). When the lift pins 711 completely place the substrate 9 onthe auxiliary ring 31, the thermal processing apparatus 1 performsthermal processing on the substrate 9 through steps similar to thosefollowing the step S18 shown in FIG. 7.

When the diameter of the inner peripheral surface 310 of the auxiliaryring 31 is unknown, the thermal processing apparatus 1 can obtain theposition of the center of the auxiliary ring 31 by further repeatedlyrotating the auxiliary ring 31 and capturing images of at least threeportions of the auxiliary ring 31.

As hereinabove described, the thermal processing apparatus 1 accordingto the third preferred embodiment matches the centers of the substrate 9and the auxiliary ring 31 with each other with the single image pickuppart 62.

FIG. 16 illustrates the flow of operations of introducing a substrate 9into a thermal processing apparatus 1 according to a fourth preferredembodiment of the present invention. The thermal processing apparatus 1according to the fourth preferred embodiment is similar in structure tothe thermal processing apparatus 1 according to the second preferredembodiment, and provided with two camera units 6. It is assumed that thediameter of an inner peripheral surface 310 of an auxiliary ring 31 andthe outer diameter of the substrate 9 are known also in the fourthpreferred embodiment.

When the substrate 9 is introduced into the thermal processing apparatus1 according to the fourth preferred embodiment (step S31), two imagepickup parts 62 capture two images 606 (see FIG. 17) including both ofthe auxiliary ring 31 and an outer edge 91 of the substrate 9 (stepS32).

FIG. 17 illustrates the two captured images 606. An image processingcircuit 65, similar to that shown in FIG. 6 but provided with only twoimage pickup parts 62 in the fourth preferred embodiment, processespreviously set processed areas 602 of the images 606 for obtainingpoints 310 a on the inner peripheral surface 310 of the auxiliary ring31 and points 90 a on an outer peripheral surface 90 of the substrate 9.The image processing circuit 65 obtains these points 310 a and 90 a asthose opposed to each other along a direction outward from a centralaxis 1 a of the thermal processing apparatus 1. A total control part 10obtains vectors 607 a and 607 b, starting from the substrate 9, betweenthe points 310 a and 90 a of the two images 606.

Since the diameter of the inner peripheral surface 310 of the auxiliaryring 31 and the outer diameter of the substrate 9 are known, the totalcontrol part 10 previously obtains the ideal distance between the innerperipheral surface 310 and the outer peripheral surface 90 for matchingthe centers of the substrate 9 and the auxiliary ring 31 with eachother. Therefore, the total control part 10 obtains the movement of thesubstrate 9 for setting the vectors 607 a and 607 b to ideal lengths(step S33).

FIG. 18 is a diagram for illustrating a method of obtaining the movementof the substrate 9. When obtaining the vectors 607 a and 607 b from thetwo images 606, the total control part 10 matches the starting points ofthese vectors 607 a and 607 b with each other and further sets vectors607 c and 607 d having the same directions as the vectors 607 a and 607b and previously obtained ideal lengths. The total control part 10obtains a vector 607 e from the sum of the vectors 607 c and 607 dtoward the sum of the vectors 607 a and 607 b as the movement.

The total control part 10 controls a transport robot 8 to move thecenter of the substrate 9 by the vector 607 e (step S34), and sets thedistance between the points 310 a and 90 a shown in FIG. 17 as the idealdistance. Thereafter the transport robot 8 places the substrate 9 on theauxiliary ring 31 while matching the centers thereof with each other(step S35).

As hereinabove described, the thermal processing apparatus 1 accordingto the fourth preferred embodiment simultaneously captures images of theouter edge 91 of the substrate 9 and the auxiliary ring 31 with the twoimage pickup parts 62 and positions the substrate 9 and the auxiliaryring 31 through the previously obtained distance between the innerperipheral surface 310 of the auxiliary ring 31 and the outer peripheralsurface 90 of the substrate 9.

FIG. 19 illustrates a thermal processing apparatus 1 according to afifth preferred embodiment of the present invention in a similar mannerto FIG. 10. The thermal processing apparatus 1, similar in structure tothat according to the first preferred embodiment, is provided with threecamera units 6. An arm 82 of a transport robot 8 is provided with anotch 821, not to hinder the camera units 6 from picking up images.

Also in the thermal processing apparatus 1 according to the fifthpreferred embodiment, image pickup parts 62 of the camera units 6capture images of a substrate 9 introduced into the thermal processingapparatus 1. Thus, the camera units 6 capture three images equivalent tothe images 606 illustrated in FIG. 17. The thermal processing apparatus1 obtains vectors 608 a, 608 b and 608 c reaching points 310 a on aninner peripheral surface 310 of an auxiliary ring 31 from points 90 a ofan outer peripheral surface 90 of the substrate 9 in the respectiveimages similar to the images 606, similarly to the thermal processingapparatus 1 according to the fourth preferred embodiment.

FIG. 20 illustrates matched starting points of the obtained threevectors 608 a, 608 b and 608 c. A total control part 10 obtains anaverage vector 608 e of the three vectors 608 a, 608 b and 608 c as themovement of the substrate 9. The thermal processing apparatus 1 movesthe substrate 9 by the average vector 608 e, thereby substantiallymatching the centers of the substrate 9 and the auxiliary ring 31 witheach other, i.e., substantially equalizes the lengths of the threevectors 608 a, 608 b and 608 c with each other after the movement.

While the centers of the substrate 9 and the auxiliary ring 31 do notcoincide with each other in a strict sense when the thermal processingapparatus 1 moves the substrate 9 by the average vector 608 e, thecenter of the substrate 9 introduced into the thermal processingapparatus 1 is approximate to that of the auxiliary ring 31 and thethree camera units 6 are uniformly arranged every 120° about a centralaxis 1 a as shown in FIG. 19, and hence the thermal processing apparatus1 can sufficiently approach the center of the substrate 9 to that of theauxiliary ring 31 by moving the substrate 9 by the average vector 608 e.The total control part 10 may alternatively obtain the movement byanother method of obtaining a vector toward the circumcenter of atriangle formed by the points of the three vectors 608 a, 608 b and 608c, for example.

The thermal processing apparatus 1 according to the fifth preferredembodiment can render the distance between the inner peripheral surface310 of the auxiliary ring 31 and the outer peripheral surface 90 of thesubstrate 9 constant by simultaneously capturing images of the outeredge 91 of the substrate 9 and the auxiliary ring 31 with the threeimage pickup parts 62 also when the diameter of the inner peripheralsurface 310 of the auxiliary ring 31 or the outer diameter of thesubstrate 9 is unknown. Consequently, the thermal processing apparatus 1can match the centers of the substrate 9 and the auxiliary ring 31 witheach other.

FIG. 21 is a longitudinal sectional view showing a thermal processingapparatus 1 according to a sixth preferred embodiment of the presentinvention, and FIG. 22 is a plan view showing a portion around a supportring group 30. FIGS. 21 and 22 show the thermal processing apparatus 1immediately after receiving a substrate 9 introduced into the same withan arm 82.

The thermal processing apparatus 1 according to the sixth preferredembodiment is similar in structure to the thermal processing apparatus 1according to the first preferred embodiment except that camera units 6are omitted. Two pin hoisting mechanisms 72 are provided forreciprocating positioning pins 721 with respect to an auxiliary ring 31from the lower surface of a reflector 13, while a plate moving mechanism73 is provided on a side portion, opposite to a gate 115, of a body part11 for horizontally reciprocating a positioning plate 731 with respectto a substrate 9 with an air cylinder. The remaining structure of thethermal processing apparatus 1 according to the sixth preferredembodiment is similar to that of the thermal processing apparatus 1according to the first preferred embodiment, and portions similar tothose in the first preferred embodiment are properly denoted by the samereference numerals.

The thermal processing apparatus 1 according to the sixth preferredembodiment first positions the auxiliary ring 31 with the pin hoistingmechanisms 72 before receiving the substrate 9. FIG. 23 illustrates thepositioned auxiliary ring 31. The auxiliary ring 31 is placed on acushion ring 32 in a slightly movable state as described with referenceto the first preferred embodiment, and the cushion ring 32 is placed ona cylindrical member 33 also in a slightly movable state (see FIG. 5).In the thermal processing apparatus 1, each pin hoisting mechanism 72moves up the positioning pin 721 having a tapered forward end alongarrow 721 a thereby bringing the positioning pin 721 into contact withthe forward end of a support part 311 for the auxiliary ring 31 andhorizontally sliding the auxiliary ring 31 along arrow 31 a.

As shown in FIG. 22, the positioning pins 721 of the two pin hoistingmechanisms 72 urge the auxiliary ring 31 thereby moving the same in adirection Y in FIG. 22. Thus, it follows that the support ring group 30moves to a constant position deviating to a direction (+Y) for locatingthe auxiliary ring 31 on a prescribed position.

When the arm 82 introduces the substrate 9 into the thermal processingapparatus 1, the plate moving mechanism 73 moves a positioning plate 731toward the substrate 9 so that two portions of the forward end of thepositioning plate 731 come into contact with an outer peripheral surface90 of the substrate 9. Thus, it follows that the substrate 9 slightlymoves in a direction (−Y) and is located on a prescribed position wherethe center thereof coincides with that of the positioned auxiliary ring31.

Thereafter a lift mechanism 71 raises the substrate 9, the arm 82retreats and the lift mechanism 71 moves down the substrate 9, therebyplacing the substrate 9 on the auxiliary ring 31 in the positionedstate.

The thermal processing apparatus 1 according to the sixth preferredembodiment mechanically positions the auxiliary ring 31 and thesubstrate 9 for rendering overlaps thereof constant.

When completely thermally processing the substrate 9, the thermalprocessing apparatus 1 stops rotating the auxiliary ring 31 at an angleof 180° with respect to that when receiving the substrate 9. Thus, itfollows that the auxiliary ring 31 is located on a position deviatingtoward the direction (−Y) and the positioning pins 721 properly positionthe auxiliary ring 31 before the same receives a subsequent substrate 9thereon.

As hereinabove described, each of the thermal processing apparatuses 1according to the second to sixth preferred embodiments also correctlypositions the substrate 9 with respect to the auxiliary ring 31 beforereceiving the substrate 9 similarly to the first preferred embodiment,whereby the thermal processing apparatus 1 can render overlaps of theouter edge 91 of the substrate 9 and the auxiliary ring 31 constant anddesign the shape of the auxiliary ring 31 to sufficiently reduce theoverlaps, suppress (pseudo) thermal capacity of the outer edge 91 andsuppress dispersion of the thermal capacity. Consequently, the thermalprocessing apparatus 1 can improve temperature uniformity of the overallsubstrate 9 and implement proper thermal processing on the substrate 9.

Each of the thermal processing apparatuses 1 according to the first,second, fourth and fifth preferred embodiments picks up images beforereceiving the substrate 9, for implementing proper placing even if theintroduced substrate 9 slightly moves on the arm 82. Further, each ofthe thermal processing apparatuses 1 according to the fourth and fifthpreferred embodiments, positioning the substrate 9 and the auxiliaryring 31 on the basis of the distance between the outer peripheralsurface 90 of the former and the inner peripheral surface 310 of thelatter, can position the substrate 9 and the auxiliary ring 31 also whenmounting positions of the camera units 6 are unknown.

While the support ring group 30 supports the substrate 9 in each of thethermal processing apparatuses 1 according to the aforementionedpreferred embodiments, the cushion ring 32 may alternatively be omittedwhile leaving the auxiliary ring 31. The auxiliary ring 31 is notrestricted to that having a step but may alternatively be a flat annularplate. Further, the auxiliary ring 31 may not support the substrate 9but the substrate 9 may be separately supported so that the annularauxiliary ring 31 is arranged around the outer edge 91 of the substrate9 at a prescribed interval. Also in this case, the thermal processingapparatus 1 can improve performance of uniformly heating the overallsubstrate 9 by correctly positioning the substrate 9 with respect to theauxiliary ring 31 and rendering the distance between the outerperipheral surface 90 of the substrate 9 and the auxiliary ring 31constant.

Each of the thermal processing apparatuses 1 according to theaforementioned preferred embodiments may alternatively measure a portionother than the inner peripheral surface 310 of the auxiliary ring 31.For example, the thermal processing apparatus 1 may detect the innermostedge of the auxiliary ring 31 (the forward end of the support part 311)or the outermost edge thereof. Further, a mark for positional detectionsuch as a mark-off line, for example, may be provided on the auxiliaryring 31.

The thermal processing apparatus 1 may illuminate the camera units 6 byweakly lighting a thermal processing lamp or inserting a fluorescenttube from the lid part 12. The opening 120 for imaging, preferablyformed on a wall surface of a lamp side with respect to the substrate 9so that the same is not exposed to processing gas in the chamber formedby the body part 11 and the lid part 12, can alternatively be formed onthe side of the reflector 13 through a necessary countermeasure.

The number of the camera units 6 may exceed that shown in each of thepreferred embodiments. In other words, the thermal processing apparatus1 can obtain the position of the center of the auxiliary ring 31 bycapturing at least two portions of the auxiliary ring 31 with at leastone image pickup part 62, and can obtain the positions of the centers ofthe auxiliary ring 31 and the substrate 9 by including at least twoimage pickup parts 62.

The mechanism of mechanically positioning the substrate 9 and theauxiliary ring 31 in the aforementioned sixth preferred embodiment is amere example, and may be replaced with another mechanism.

The lamps for irradiating the substrate 9 with light may not necessarilybe provided as the upper and lower lamp groups 41 and 42 perpendicularto each other but the thermal processing apparatus 1 may be providedwith only either the upper or lower lamp group 41 or 42. Further, thethermal processing apparatus 1 may alternatively irradiate the substrate9 with light from the upper and lower surfaces thereof.

The substrate 9 processed by the thermal processing apparatus 1 is notrestricted to a semiconductor substrate but the substrate processingapparatus 1 can also be utilized for thermally processing a glasssubstrate for a flat panel display such as a liquid crystal display or aplasma display.

FIG. 24 is a longitudinal sectional view showing the structure of athermal processing apparatus 1001 according to a seventh preferredembodiment of the present invention. FIG. 24 omits parallel obliquelines with respect to sections of details.

The thermal processing apparatus 1001 irradiates a substrate 9 withlight in a prescribed atmosphere thereby performing various processingsuch as oxidization, annealing and CVD accompanied by heating on thesubstrate 9. In the thermal processing apparatus 1001, a body part 1011forming the apparatus body, a lid part 1012 covering the upper portionof the body part 1011 and a reflector 1013 arranged on the centralbottom surface of the body part 1011 form a chamber. A chamber window1021 of quartz vertically partitions the internal space of the chamber,and an auxiliary ring group 1030 supports the substrate 9 in a lowerprocessing space 1010. An O-ring (not shown) seals the clearance betweenthe chamber window 1021 and the body part 1011, which has a cylindricalinner side surface.

A plurality of gas inlets 1111 and a plurality of outlets 1112 areformed on the side wall of the body part 1011. The processing space 1010performs gas replacement by (enforcedly) discharging gas from theoutlets 1112 while introducing gas (e.g., nitrogen, oxygen or the like)responsive to the type of processing performed on the substrate 9through the gas inlets 1111. The thermal processing apparatus 1001 isprovided with a shower plate 1022 of quartz formed with a large numberof holes between the substrate 9 and the chamber window 1021, forhomogeneously supplying the gas introduced from the gas inlets 1111 tothe upper surface of the substrate 9 through the shower plate 1022. Thegas employed for the processing is guided to the outlets 1112 from belowthe processing space 1010.

A cylindrical member 1033 centered at a central axis 1 a of theapparatus 1001 supports the auxiliary ring group 1030, while a couplingmember 1361 is mounted on the lower end of the cylindrical member 1033.Another coupling member 1362 opposed to the coupling member 1361 isprovided under the body part 1011 so that the coupling members 1361 and1362 form a magnetic coupling mechanism. The coupling member 1362rotates about the central axis 1 a through a motor 1363. Thus, thecoupling member 1361 provided in the body part 1011 rotates due tomagnetic action, while the substrate 9 and the auxiliary ring group 1030rotate about the central axis 1 a while keeping the direction of themain surface constant. The cylindrical member 1033 is made of quartz, inorder to suppress thermal expansion in heating.

An annular screening ring 1034 is provided outside the auxiliary ringgroup 1030. The body part 1011 supports the screening ring 1034, whichin turn covers the outer side of the auxiliary ring group 1030 and aclearance 1010 a between the cylindrical member 1033 and the body part1011.

The lower surface of the lid part 1012 of the thermal processingapparatus 1001 defines a reflecting surface (hereinafter referred to as“reflector”) 1121 opposed to the upper surface of the substrate 9, and abar-shaped upper lamp group 1041 is arranged along the reflector 1121 sothat respective lamps are along a direction X. The reflector 1121reflects a component of light upwardly emitted from the upper lamp group1041 and applies the same to the substrate 9. The upper lamp group 1041is formed by infrared halogen lamps, for example. A bar-shaped lowerlamp group 1042 is arranged under the upper lamp group 1041, i.e.,between the upper lamp group 1041 and the substrate 9, so thatrespective lamps are along a direction Y perpendicularly to the upperlamp group 1041.

Each of the upper and lower lamp groups 1041 and 1042 is divided intosmall groups in response to distances from the central axis 1 a, and thegroups are individually connected to a lamp control part and suppliedwith power independently of each other.

A plurality of radiation thermometers 1051 are mounted under thesubstrate 9 outwardly from the central axis 1 a. The radiationthermometers 1051 receive infrared light from the substrate 9 through awindow member 1050 provided on the reflector 1013 thereby measuring thetemperature of the substrate 9. The plurality of radiation thermometers1051 measure the temperature of the substrate 9 placed on the auxiliaryring group 1030 and rotated in response to distances from the centralaxis 1 a. The thermal processing apparatus 1001 controls the lamps sothat the temperature of the substrate 9 is as uniform as possibleaccording to the results of measurement. At this time, the substrate 9,the auxiliary ring group 1030 and the screening ring 1034 inhibit lightfrom the lamp groups 1041 and 1042 from entering the radiationthermometers 1051, so that the radiation thermometers 1051 correctlymeasure the temperature.

FIG. 25 illustrates the inside of the screening ring 1034 along arrowsA1 in FIG. 24, and FIG. 26 is an enlarged sectional view of theauxiliary ring group 1030 supporting the substrate 9.

As shown in FIGS. 25 and 26, the auxiliary ring group 1030 is formed byfirst and second annular auxiliary rings 1031 and 1032 spreading alongthe outer periphery of the substrate 9, so that the first auxiliary ring1031 receives the substrate 9 thereon and the second auxiliary ring 1032supports the first auxiliary ring 1031 from outside. Both of the firstand second auxiliary rings 1031 and 1032 are made of silicon carbide(SiC) having specific heat capacity close to that of the substrate 9,and provided in the form of tori centered at the central axis 1 a. Thefirst and second auxiliary rings 1031 and 1032 are heated integrallywith the substrate 9, thereby improving in-plane uniformity of thetemperature of the substrate 9.

The first auxiliary ring 1031 has an annular support part 1311projecting toward the central axis 1 a on its inner peripheral surface1310. The support part 1311 comes into contact with the outer edge ofthe substrate 9, transported into the processing space 1010 by anexternal transport mechanism, from below thereby supporting thesubstrate 9. When the substrate 9 is placed on the first auxiliary ring1031, an outer peripheral surface 90 of the substrate 9 and an innerperipheral surface 1310 of the first auxiliary ring 1031 are opposed toeach other.

As shown in FIG. 26, annular concave portions 1312 and 1322 centered atthe central axis 1 a are formed on the lower surfaces of the first andsecond auxiliary rings 1031 and 1032 respectively, while a convexportion 1321 centered at the central axis 1 a is provided on an innerend of the second auxiliary ring 1032 to annularly project upward. Theupper surface of the convex portion 1321 comes into contact with thebottom surface (the downwardly directed surface) of the concave portion1312 of the first auxiliary ring 1031 so that the second auxiliary ring1032 supports the first auxiliary ring 1031. Another convex portion 1331centered at the central axis 1 a is annularly provided also on the uppersurface of the cylindrical member 1033 of quartz to project upward andthe upper surface of this concave portion 1331 comes into contact withthe bottom surface of the concave portion 1322 of the second auxiliaryring 1032, so that the cylindrical member 1033 supports the secondauxiliary ring 1032.

The first and second auxiliary rings 1031 and 1032 and the cylindricalmember 1033 are provided in the form of rings while the support part1311, the concave portions 1312 and 1322 and the convex portions 1321and 1331 are annularly shaped thereby inhibiting processing gas fromreaching the lower surface of the substrate 9.

The screening ring 1034 is made of silicon carbide, and provided tospread along the outer periphery of the substrate 9 while covering theouter side of the second auxiliary ring 1032, as shown in FIGS. 25 and26. As shown in FIG. 26, an annular concave portion 1342 centered at thecentral axis 1 a is formed on the lower surface of the screening ring1034, and a plurality of support parts 1035 of quartz are fixed to thebody part 1011 on a circumference centered at the central axis 1 a (seeFIG. 25). An upwardly projecting support pin 1351 is formed on the uppersurface of the support part 1035 so that the upper surface of thesupport pin 1351 comes into contact with the bottom surface of theconcave portion 1342 of the screening ring 1034 thereby supporting thescreening ring 1034. The body part 1011 is made of SUS and cooled by awater-cooling mechanism (not shown).

A downwardly projecting annular projection 1343 is provided on an end ofthe screening ring 1034 closer to the central axis 1 a, while anupwardly projecting annular projection 1323 is formed on an outer end ofthe second auxiliary ring 1032. The projections 1323 and 1343 form anoptical labyrinth, for preventing light from entering a clearance 1010 abetween the body part 1011 and the cylindrical member 1033.

FIG. 27 illustrates the auxiliary ring group 1030 and the screening ring1034 in an enlarged manner. When the thermal processing apparatus 1001does not heat the substrate 9, a cylindrical surface 1312 a, centered atthe central axis 1 a, of the concave portion 1312 of the first auxiliaryring 1031 directed toward the substrate 9 and an outwardly directedcylindrical surface 1321 a of the convex portion 1321 of the secondauxiliary ring 1032 are opposed to each other and approximatelypositioned (including a state of coming into contact with each other onany position; this also applies to the following description) as shownin FIG. 27. Similarly, a cylindrical surface 1322 a of the concaveportion 1322 of the second auxiliary ring 1032 directed toward thesubstrate 9 and an outwardly directed cylindrical surface 1331 a of theconvex portion 1331 of the cylindrical member 1033 are opposed to eachother and approximately positioned. Further, a cylindrical surface 1342a of the concave portion 1342 of the screening ring 1034 directed towardthe substrate 9 and an outwardly directed surface 1351 a, i.e., theouter portion of the side surface, of the support pin 1351 of thesupport part 1035 are opposed to each other and approximatelypositioned.

FIG. 28 illustrates the auxiliary ring group 1030 and the screening ring1034 of the thermal processing apparatus 1001 heating the substrate 9.While the thermal processing apparatus 1001 heats the first and secondauxiliary rings 1031 and 1032 integrally with the substrate 9, thetemperature is reduced outwardly from the substrate 9 and hence thetemperature of the first auxiliary ring 1031 is higher than that of thesecond auxiliary ring 1032. Therefore, the length of the first auxiliaryring 1031 extended by expansion (i.e., change of the radius about thecentral axis 1 a) is larger than that of the second auxiliary ring 1032extended by expansion. Thus, the clearance, having a width L1 in FIG.28, between the cylindrical surfaces 1312 a and 1321 a of the concaveportion 1312 and the convex portion 1321 of the first and secondauxiliary rings 1031 and 1032 is increased.

The second auxiliary ring 1032 is made of silicon carbide and thecylindrical member 1033 is made of quartz as hereinabove described whilethe thermal expansion coefficient of silicon carbide is larger than thatof quartz by about one place, and hence the clearance, having a width L2in FIG. 28, between the cylindrical surfaces 1322 a and 1331 a of theconcave portion 1322 and the convex portion 1331 of the second auxiliaryring 1032 and the cylindrical member 1033 is increased when the thermalprocessing apparatus 1001 heats the substrate 9. Further, the supportpart 1035 is mounted on the body part 1011 cooled to less than 100° C.,and hence the clearance, having a width L3 in FIG. 28, between thecylindrical surface 1342 a of the concave portion 1342 of the screeningring 1034 and the surface 1351 a of the support pin 1351 of the supportpart 1035 is increased when the thermal processing apparatus 1001 heatsthe screening ring 1034.

More specifically, the clearances between the concave portions 1312,1322 and 1342 and the convex portions 1321 and 1331 and the support pin1351 are set to 0.1 mm in the state shown in FIG. 27 when the diameterof the substrate 9 processed by thermal processing apparatus 1001 is 300mm. The diameters of the auxiliary ring group 1030 and the screeningring 1034 are increased by about 1.5 mm when heated to 1100 to 1200° C.,and hence the radial widths of the concave portions 1312, 1322 and 1342are set larger than the widths of the convex portions 1321 and 1331 andthe support pin 1351 by about 1 mm. In other words, slacks of about 1 mmare provided. Thus, the thermal processing apparatus 1001 can preventcracking resulting from excess stress also when the first and secondauxiliary rings 1031 and 1032 and the screening ring 1034 are expandedby heating.

The support pin 1351 supports the screening ring 1034, therebypreventing the clearance between the outer side of the screening ring1034 and the body part 1011 from storing gas. The support pin 1351 mayalternatively be replaced with an annular recessed member centered atthe central axis 1 a.

When completely processing the substrate 9, the thermal processingapparatus 1001 stops supplying power to the lamp groups 1041 and 1042and reduces the temperature in the processing space 1010. Consequently,the first and second auxiliary rings 1031 and 1032 and the screeningring 1034 are contracted while the diameters of the cylindrical member1033 and the arrangement of the support part 1035 are also slightlyreduced, so that the widths L1 to L3 shown in FIG. 28, i.e., theclearances between the cylindrical surfaces 1321 a and 1312 a, betweenthe cylindrical surfaces 1331 a and 1322 a and between the surface 1351a and the cylindrical surface 1342 a are reduced and the arrangement ofthe respective structures returns to the state shown in FIG. 27.

The thermal processing apparatus 1001 is so designed as to set thewidths L1 to L3 to slight distances at the ordinary temperature. Even ifthe center of the first or second auxiliary ring 1031 or 1032 or thescreening ring 1034 deviates from the central axis 1 a of the apparatus1001 in heating, therefore, it follows that the concave portion 1312,1322 or 1342 comes into contact with the convex portion 1321 or 1331 orthe support pin 1351 on any position to substantially return thepositions of the rings 1031, 1032 and 1034 to the states shown in FIG.27. Consequently, the thermal processing apparatus 1001 Limits deviationof the first and second auxiliary rings 1031 and 1032 and the screeningring 1034 therein also when repeating thermal processing.

When designed to set the widths L1 to L3 to 0.1 mm under a lowtemperature, for example, the thermal processing apparatus 1001 limitsthe quantities of deviation of the center of the first auxiliary ring1031 and the centers of the second auxiliary ring 1032 and the screeningring 1034 with respect to the central axis 1 a to about 0.2 mm at themaximum and about 0.1 mm at the maximum respectively.

As a result, the thermal processing apparatus 1001 reliably preventslight from the lamps from entering the radiation thermometers 1051 alsowhen suppressing overlaps between the substrate 9 and the firstauxiliary ring 1031, between the first and second auxiliary rings 1031and 1032 and between the second auxiliary ring 1032 and the screeningring 1034 respectively. Consequently, the thermal processing apparatus1001 can suppress temperature irregularity caused in the substrate 9 andthe first and second auxiliary rings 1031 and 1032 due to large overlapsor circumferentially inconstant overlaps, for improving temperatureuniformity of the substrate 9 in heating. Further, the position of thefirst auxiliary ring 1031 is substantially constant in non-heating,whereby the thermal processing apparatus 1001 can readily place thesubstrate 9 on the first auxiliary ring 1031.

While the annularly recessed concave portion 1342 is provided on thelower surface of the screening ring 1034 in the aforementioned seventhpreferred embodiment, slots 1344 may alternatively formed on a screeningring 1034 as shown in FIG. 29, for example, for positioning thescreening ring 1034 with support pins 1351 and the slots 1344 under alow temperature. In this case, outer surfaces, directed toward asubstrate 9, of the slots 1344 and outwardly directed side surfaces ofthe support pins 1351 approach or come into contact with each otherunder a low temperature thereby preventing the screening ring 1034 fromdisplacement. Similarly, the first or second auxiliary ring 1031 or 1032may alternatively be formed with a slot or a groove in the form of aslot in place of the concave portion 1312 or 1322 and the secondauxiliary ring 1032 or the cylindrical member 1033 may be provided witha substantially pin-shaped convex portion engaged in the slot in placeof the convex portion 1321 or 1331.

As shown in FIG. 30, first and second auxiliary rings 1031 and 1032 anda screening ring 1034 may be formed with downwardly projectingsubstantially pin-shaped convex portions 1310 a, 1320 a and 1340 arespectively, and the second auxiliary ring 1032, a cylindrical member1033 and a support part 1035 may be formed with concave portions 1320 b,1330 b and 1350 b engaged with the concave portions 1310 a, 1320 a and1340 a respectively. In this case, surfaces of the side surfaces of theconvex portions 1310 a, 1320 a and 1340 a directed toward a substrate 9and outwardly directed surfaces of the concave portions 1320 b, 1330 band 1350 b approach or come into contact with each other under a lowtemperature thereby preventing the first and second auxiliary rings 1031and 1032 and the screening ring 1034 from displacement.

As hereinabove described, various structures can be employed forlimiting the positions of ring-shaped members such as the auxiliary ringgroup 1030 and the screening ring 1034 spreading along the outerperiphery of the substrate 9 under a low temperature. When thering-shaped members expand beyond support-side members in heating due totemperature difference or difference in thermal expansion coefficient,surfaces of the ring-shaped members directed to the substrate 9 andopposed surfaces of the support-side members are generally soapproximated to each other that clearances between the surfaces oppositeto each other are reduced and displacement of the ring-shaped memberscan be limited under a low temperature.

While the ring-shaped members expand beyond the support-side members inheating due to temperature difference or difference in thermal expansioncoefficient in the aforementioned seventh preferred embodiment, thesupport-side members may conceivably expand beyond the ring-shapedmembers in heating depending on selected materials. In this case,outwardly directed surfaces of the ring-shaped members and opposedsurfaces (directed to the substrate 9) of the support-side members areso approximated to each other that clearances between the surfacesopposite to each other are reduced and displacement of the ring-shapedmembers can be limited under a low temperature.

The auxiliary ring group 1030 in the aforementioned seventh preferredembodiment may alternatively be formed by a single auxiliary ring, whilea separately provided support member may support the substrate 9 so thatthe auxiliary ring group 1030 outwardly spreads from the outer edge ofthe substrate 9.

The lamps for irradiating the substrate 9 with light may not necessarilybe provided as the upper and lower lamp groups 1041 and 1042perpendicular to each other, but the thermal processing apparatus 1001may alternatively be provided with only either the upper or lower lampgroup 1041 or 1042. Further, the thermal processing apparatus 1001 mayirradiate the substrate 9 with lamp light from the upper and lowersurfaces thereof.

The substrate 9 processed by the thermal processing apparatus 1001 isnot restricted to a semiconductor substrate but the substrate processingapparatus 1001 can also be utilized for thermally processing a glasssubstrate for a flat panel display such as a liquid crystal display or aplasma display.

FIGS. 31 and 32 are longitudinal sectional views showing the structureof a thermal processing apparatus 2001 according to an eighth preferredembodiment of the present invention, and cutting planes in FIGS. 31 and32 perpendicularly intersect with each other at a central axis 1 a ofthe thermal processing apparatus 2001 directed to a direction Z. FIGS.31 and 32 omit parallel oblique lines with respect to sections ofdetails.

The thermal processing apparatus 2001 has a body part 2011 forming theapparatus body, a lid part 2012 covering the upper portion of the bodypart 2011 and a reflector 2013 arranged on the central bottom surface ofthe body part 2011, which form an internal space. A chamber window 2021of quartz vertically partitions the internal space, and a support ringgroup 2030 described later supports a substrate 9 in a lower processingspace 2010. An O-ring (not shown) seals the clearance between thechamber window 2021 and the body part 2011, which has a cylindricalinner side surface.

A plurality of gas inlets 2111 and a plurality of outlets 2112 areformed on the side wall of the body part 2011. The processing space 2010performs gas replacement by (enforcedly) discharging gas from theoutlets 2112 while introducing gas (e.g., nitrogen, oxygen or the like)responsive to the type of processing performed on the substrate 9through the gas inlets 2111. The thermal processing apparatus 2001 isprovided with a shower plate 2022 of quartz formed with a large numberof holes between the substrate 9 and the chamber window 2021, forhomogeneously supplying the gas introduced from the gas inlets 2111 tothe upper surface of the substrate 9 through the shower plate 2022. Thegas employed for the processing is guided to the outlets 2112 from belowthe processing space 2010.

As shown in FIGS. 31 and 32, a cylindrical member 2033 centered at acentral axis 1 a supports the support ring group 2030, while a couplingmember 2331 is mounted on the lower end of the cylindrical member 2033.Another coupling member 2332 opposed to the coupling member 2331 isprovided under the body part 2011 so that the coupling members 2331 and2332 form a magnetic coupling mechanism. The coupling member 2332rotates about the central axis 1 a through a motor 2333 shown in FIG.32. Thus, the coupling member 2331 provided in the body part 2011rotates due to magnetic action, while the substrate 9 and the supportring group 2030 rotate about the central axis 1 a.

The lower surface of the lid part 2012 defines a reflecting surface(hereinafter referred to as “reflector”) 2121 opposed to the uppersurface of the substrate 9, and a bar-shaped upper lamp group 2041 isarranged along the reflector 2121 so that respective lamps are along adirection X in FIG. 31. The reflector 2121 reflects a component of lightupwardly emitted from the upper lamp group 2041 and applies the same tothe substrate 9.

A bar-shaped lower lamp group 2042 is arranged under the upper lampgroup 2041, i.e., between the upper lamp group 2041 and the substrate 9,so that respective lamps are along a direction Y. In other words, theupper and lower lamp groups 2041 and 2042 are mounted on the lid part2012 to be perpendicularly to each other.

Each of the upper and lower lamp groups 2041 and 2042 is divided intosmall groups in response to distances from the central axis 1 a. FIG. 32shows lamps 2411, 2412, 2413 and 2414 of the upper lamp group 2041grouped successively from the side of the central axis 1 a, and FIG. 31shows lamps 2421, 2422, 2423 and 2424 of the lower lamp group 2042grouped successively from the side of the central axis 1 a.

FIG. 33 is a block diagram showing the connectional relation between thegrouped lamps 2411, 2412, 2413, 2414, 2421, 2422, 2423 and 2424 and alamp control part 2006 supplying power to the lamps 2411, 2412, 2413,2414, 2421, 2422, 2423 and 2424 (each block shows a plurality of lamps).As shown in FIG. 33, the grouped lamps 2411, 2412, 2413 and 2414 of theupper lamp group 2041 and the grouped lamps 2421, 2422, 2423 and 2424 ofthe lower lamp group 2042 are individually connected to the lamp controlpart 2006, and supplied with power independently of each other. Thus,intensity distribution of light applied to the upper surface of thesubstrate 9 is controlled.

FIG. 34 illustrates the inside of the cylindrical member 2033 alongarrows A2 in FIG. 32, and FIG. 35 is an enlarged sectional view showingthe support ring group 2030 supporting the substrate 9.

As shown in FIGS. 34 and 35, the support ring group 2030 is formed by anannular auxiliary ring 2031 receiving the substrate 9 thereon and anannular cushion ring 2032 supporting the auxiliary ring 2031 fromoutside. Both of the auxiliary ring 2031 and the cushion ring 2032 aremade of silicon carbide (SiC) having specific heat capacity close tothat of the substrate 9. The auxiliary ring 2031 has an annular supportpart 2311 projecting toward the central axis 1 a on its inner peripheralsurface 2310, so that the support part 2311 comes into contact with thesubstrate 9 transported into the processing space 2010 by an externaltransport mechanism from below thereby supporting the same. When thesubstrate 9 is placed on the auxiliary ring 2031, an outer peripheralsurface 90 of the substrate 9 and an inner peripheral surface 2310 ofthe auxiliary ring 2031 are opposed to each other while the auxiliaryring 2031 is positioned to outwardly spread from the outer edge 91 ofthe substrate 9. In the following description, the thickness of thesubstrate 9 is referred to as a substrate thickness Tw, the thickness ofthe support part 2311 is referred to as a support part thickness T andthe width of overlapping portions of the substrate 9 and the supportpart 2311 is referred to as a support width W, as shown in FIG. 35.

The aforementioned cylindrical member 2033 supports the concentricannular cushion ring 2032 supporting the auxiliary ring 2031 fromoutside. As shown in FIG. 35, engaging portions 2391 and 2392 betweenthe auxiliary ring 231 and the cushion ring 2032 and between the cushionring 2032 and the cylindrical member 2033 have clearances (slacks)respectively. Also when swollen with heat, therefore, the auxiliary ring2031 and the cushion ring 2032 are prevented from cracking resultingfrom excess stress.

As shown in FIGS. 32 and 34, a plurality of radiation thermometers 2051to 2053 are mounted under the substrate 9 outwardly from the centralaxis 1 a. The radiation thermometers 2051 to 2053 receive infrared lightfrom the substrate 9 through a window member 2050 provided on thereflector 2013 thereby measuring the temperature of the substrate 9. Theplurality of radiation thermometers 2051 to 2053 measure the temperatureof the substrate 9 placed on the support ring group 2030 and rotated inresponse to distances from the central axis 1 a. At this time, thesubstrate 9, the support ring group 2030 and the cylindrical member 2033inhibit infrared radiation from the lamp groups 2041 and 2042 fromentering the radiation thermometers 2051 to 2053, so that the radiationthermometers 2051 to 2053 correctly measure the temperature.

When performing processing accompanied by heating on the substrate 9,the thermal processing apparatus 2001 controls power supplied to thelamps 2411 and 2421 in response to results of measurement of theradiation thermometers 2051 while controlling power supplied to thelamps 2412, 2422, 2413 and 2423 in response to results of measurement ofthe radiation thermometers 2052 and 2053 respectively, for example. Thethermal processing apparatus 2001 supplies power to the lamps 2414 and2424 mainly irradiating the auxiliary ring 2031 with infrared radiationaccording to a predetermined profile. At this time, a rotation mechanismformed by the motor 2333 and the coupling mechanism rotates thesubstrate 9 and the support ring group 2030, and the thermal processingapparatus 2001 controls heating of the substrate 9 so that thetemperature thereof is as uniform as possible.

FIG. 36 illustrates the relation between thickness difference D (seeFIG. 2) between the outer edge and the center of the substrate 9 and theproduct (T×W) of the support part thickness T and the support width Wwhen forming an oxide film through an RTP in the thermal processingapparatus 2001 and varying the support part thickness T and the supportwidth W shown in FIG. 35 as shown in FIG. 37.

In measurement, the substrate 9 having a diameter 200 mm and a substratethickness Tw of 0.725 mm was rapidly heated to a target temperature of1100° C. at about 100° C./s and thereafter held at the targettemperature for 60 seconds. In order to obtain the thickness differenceD, thicknesses were measured on a position (corresponding to that of thedistance R2 in FIG. 2) of 2 mm inside the outer edge of the substrate 9and a position (corresponding to that of the distance R1 in FIG. 2) of10 mm inside the outer edge of the substrate 9 respectively. It has beenconfirmed that the thickness was substantially constant inside theposition of 10 mm inside the outer edge of the substrate 9 and theaverage thickness was about 11 nm.

It is understood from FIG. 36 that proportionality is present betweenthe thickness difference D and the product (T×W), as shown by a straightline Z. Assuming that allowable dispersion of the thickness is ±1%,allowable thickness difference D is about 0.22 nm (2% of the averagethickness of 11 nm). According to the straight line Z, therefore, it canbe said possible to reduce dispersion of the thickness to not more than±1% if the product (T×W) is not more than about 1.5 mm². Consideringthat dispersion of the thicknesses is influenced by the support partthickness T and the support width W as the substrate thickness Tw isreduced and that the substrate 9 having the substrate thickness Tw of0.725 mm was used in measurement, it is estimated that dispersion of thethickness can be rendered within ±1% of the average thickness when anumerical value (T₁×W₁) obtained in terms of “mm²,” of the product (T×W)is not more than about twice a numerical value (TW₁) obtained in termsof “mm” of the substrate thickness TW. In other words, temperatureuniformity of the substrate 9 can be improved by satisfying relationexpressed as ((T₁×W₁)<(Tw₁ ×2)).

When the thermal processing apparatus 2001 actually perform the RTP, thethermal capacity per unit area is increased on a portion where thesubstrate 9 and the auxiliary ring 2031 overlap with each other, i.e.,on the outer edge of the substrate 9, in a temperature increase stepsimilar to that shown in FIG. 1 (between the times t1 and t2), and hencetemperature increase is retarded. Therefore, the thermal processingapparatus 2001 sets power supplied to the lamps 2414 and 2424 higherthan that supplied to the remaining lamps 2411, 2412, 2413, 2421, 2422and 2423 in order to sufficiently heat the auxiliary ring 2031.

According to this setting, however, the temperature of the auxiliaryring 2031 exceeds that of the substrate 9 in a holding step (between thetimes t2 and t3) such that heat is transferred from the auxiliary ring2031 to increase the temperature of the outer edge of the substrate 9beyond those of the remaining portions. The thermal processing apparatus2001 limits the shape, shown by the support part thickness T and thesupport width W, of the portion where the substrate 9 and the auxiliaryring 2031 overlap with each other by the substrate thickness Tw therebysuppressing temperature difference between the outer edge and the centerof the substrate 9 in the holding step. In other words, the thermalprocessing apparatus 2001 improves temperature uniformity of thesubstrate 9 by limiting a heat transfer path from the auxiliary ring2031 to the substrate 9.

While it can be said preferable that the product (T×W) is not more than1.5 mm² when forming a film of an ordinary thickness of about 10 nm fromFIG. 36, it is preferable that the support part thickness T and thesupport width W are rendered not more than 0.5 mm and not more than 3 mmrespectively considering that this condition has been guided from themeasurement range shown in FIG. 37. In consideration of a point thatreliable measurement results are obtained, it can be said morepreferable to render the product (T×W) and the support part thickness Tnot more than 1.2 mm² and not more than 0.4 mm respectively.

While the above eighth preferred embodiment has been described withreference to formation of an oxide film on the substrate 9, the thermalprocessing apparatus 2001 may alternatively perform processingaccompanied by heating other than formation of an oxide film. Further,the size and the thickness of the substrate 9 may also be varied.

The support ring group 2030 may not necessarily be formed by theauxiliary ring 2031 and the cushion ring 2032, but the cushion ring 2032may be omitted while leaving only the auxiliary ring 2031.

The shape of the auxiliary ring 2031 is not restricted to that in theaforementioned eighth preferred embodiment but the auxiliary ring 2031may alternatively be a simple plate-shaped torus having no innerperipheral surface 2310 (i.e., the support part thickness T defines thethickness of the auxiliary ring 2031), or an annular projection having asurface opposed to the outer peripheral surface of the substrate 9 maybe provided on the upper surface of a simple plate-shaped torus.

While the thermal processing apparatus 2001 rotates the substrate 9, theformer may rotate the latter only at need.

The lamps for irradiating the substrate 9 with light may not necessarilybe provided as the upper and lower lamp groups 2041 and 2042perpendicular to each other but the thermal processing apparatus 2001may be provided with only either the upper or lower lamp group 2041 or2042. Further, the thermal processing apparatus 2001 may alternativelyirradiate the substrate 9 with light from the upper and lower surfacesthereof.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention.

1. A thermal processing apparatus capable of heating a substrate withlight, comprising: a lamp irradiating said substrate with said light; aring enclosing the outer edge of said substrate and outwardly spreadingfrom said outer edge; and an image pickup system capturing images of aplurality of portions of said ring.
 2. The thermal processing apparatusaccording to claim 1, further comprising a rotation mechanism rotatingsaid ring while directing said ring toward a prescribed direction. 3.The thermal processing apparatus according to claim 1, wherein saidimage pickup system includes a plurality of image pickup parts set ondifferent positions.
 4. The thermal processing apparatus according toclaim 3, wherein said image pickup system includes at least three saidimage pickup parts set on different positions.
 5. The thermal processingapparatus according to claim 1, further comprising a chamber storingsaid lamp, said ring and said substrate, wherein said chamber is formedwith an opening so that said image pickup system captures said images ofsaid ring from outside said chamber through said opening.
 6. The thermalprocessing apparatus according to claim 5, wherein said opening isformed on a position closer to said lamp than said substrate.
 7. Thethermal processing apparatus according to claim 5, further comprising alight source part emitting illumination light for illuminating said ringthrough said opening.
 8. A thermal processing apparatus capable ofheating a substrate with light, comprising: a lamp irradiating saidsubstrate with said light; a ring enclosing the outer edge of saidsubstrate and outwardly spreading from said outer edge; and an imagepickup system comprising a plurality of image pickup parts capturingimages of said outer edge of said substrate.
 9. The thermal processingapparatus according to claim 8, wherein said image pickup systemcomprises at least three said image pickup parts.
 10. The thermalprocessing apparatus according to claim 8, wherein said image pickupsystem also captures an image of said ring.
 11. The thermal processingapparatus according to claim 10, wherein the respective ones of saidplurality of image pickup parts simultaneously capture respective saidimages of said outer edge of said substrate and said ring.
 12. Thethermal processing apparatus according to claim 8, further comprising achamber storing said lamp, said ring and said substrate, wherein anopening is formed in said chamber so that said image pickup systemcaptures said images of said outer edge of said substrate from outsidesaid chamber through said opening.
 13. The thermal processing apparatusaccording to claim 12, wherein said opening is formed on a positioncloser to said lamp than said substrate.
 14. The thermal processingapparatus according to claim 12, further comprising a light source partemitting illumination light illuminating at least said outer edge ofsaid substrate through said opening.